Using transcriptomics to reveal the molecular mechanism of higher alcohol metabolism in Saccharomyces cerevisiae

Abstract

High alcohols are important flavor compounds in alcoholic beverages, but high concentration of high alcohols is harmful to human health. Higher alcohol synthesis pathways in brewing microorganisms have been investigated, but the interactions between key genes remain to be explored, especially in industrial strains of Saccharomyces cerevisiae. The PDC1 gene was considered to be the main encoding gene of α-keto acid decarboxylase, and its deletion resulted in a 92.23% increase in isobutanol production and a 14.89% decrease in isoamyl alcohol production. Transcriptome sequencing was used to explore the effects of PDC1 gene deletion on global gene transcription levels, and deletion strategies were utilized to verify the effects of differential genes on higher alcohol production. Deletion of differential gene HMLALPHA2 increased isobutanol production by 26.23%, and decreased isoamyl alcohol and 2-phenylethanol production by 30.31% and 22.35%, respectively. The THI2, THI4, THI20 genes were proved to be related to n-propanol synthesis. In addition, HMRA2 and SIR3 genes were found to influence isoamyl alcohol synthesis pathways, and their deletion increased isoamyl alcohol production by 25.18% and 21.76%. Our discovery of new target genes is useful for elucidating the molecular mechanisms of higher alcohols and the construction of novel low-producing higher alcohol strains.